Compiling library in g++ using C++11

I'm been attempting to compile an open-source C++ library (QuantLib-1.7) on my mac for several days but I seem to be encountering some kind of C++11 compatibility issue.

When I run make && sudo make install from the terminal the compilation seems to work except for a bunch of errors of the form

Making all in BermudanSwaption
g++ -DHAVE_CONFIG_H -I. -I../../ql  -I../.. -I../.. -I/opt/local/include  -g -O2 -MT BermudanSwaption.o -MD -MP -MF .deps/BermudanSwaption.Tpo -c -o BermudanSwaption.o BermudanSwaption.cpp
In file included from BermudanSwaption.cpp:22:
In file included from ../../ql/quantlib.hpp:43:
In file included from ../../ql/experimental/all.hpp:25:
In file included from ../../ql/experimental/volatility/all.hpp:21:
In file included from ../../ql/experimental/volatility/zabr.hpp:31:
In file included from ../../ql/math/statistics/incrementalstatistics.hpp:35:
In file included from /opt/local/include/boost/accumulators/statistics/stats.hpp:14:
In file included from /opt/local/include/boost/accumulators/statistics_fwd.hpp:12:
/opt/local/include/boost/mpl/print.hpp:50:19: warning: in-class initialization
  of non-static data member is a C++11 extension [-Wc++11-extensions]
const int m_x = 1 / (sizeof(T) - sizeof(T));
              ^
1 warning generated.

I'm guessing this has something to do with g++ not being correctly configured for C++11. I'm familiar with the fact that C++11 can be invoked by compiling with g++ -std=c++11. However, despite a lot of googling I can't find a way to modify the makefile such that -std=c++11 is called when I run make && sudo make install.

Any help would be greatly appreciated.

Here is the section of the makefile which I believe is relevant:

BOOST_INCLUDE = -I/opt/local/include
BOOST_LIB = -L/opt/local/lib
BOOST_THREAD_LIB = 
BOOST_UNIT_TEST_DEFINE = -DQL_WORKING_BOOST_STREAMS
BOOST_UNIT_TEST_LIB = boost_unit_test_framework-mt
BOOST_UNIT_TEST_MAIN_CXXFLAGS = -DBOOST_TEST_DYN_LINK
CC = gcc
CCDEPMODE = depmode=gcc3
CFLAGS = -g -O2
CPP = gcc -E
CPPFLAGS =  -I/opt/local/include
CXX = g++
CXXCPP = g++ -E
CXXDEPMODE = depmode=gcc3
CXXFLAGS = -g -O2

Here is the output from running "g++ -v":

Configured with: --prefix=/Applications/http://ift.tt/1d5DwEL --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 7.0.0 (clang-700.1.76)
Target: x86_64-apple-darwin14.5.0
Thread model: posix

Full makefile: http://ift.tt/1XfpAkO

Full error log: http://ift.tt/1SkiQeO